Percolation and capillary fluid displacement

1983 ◽  
pp. 169-183 ◽  
Author(s):  
Joel Koplik ◽  
David Wilkinson ◽  
Jorge F. Willemsen
Keyword(s):  
Fluid Displacement ◽  
Capillary Fluid

Abnormalities of the lymphatic system and impaired fluid clearance in patients with heart failure with preserved ejection fraction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
G Rossitto ◽  
S Mary ◽  
C McAllister ◽  
K.B Neves ◽  
L Haddow ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Blood Vessels ◽  
Lymphatic System ◽  
Filtration Coefficient ◽  
Funding Source ◽  
Preserved Ejection Fraction ◽  
Resistance Arteries ◽  
Fluid Extravasation ◽  
Capillary Fluid

Abstract Background Coronary and skeletal muscle microvascular dysfunction have been proposed as main factors in the pathogenesis of Heart Failure with Preserved Ejection Fraction (HFpEF). However, assessment of systemic arterial function has only been indirect thus far; most importantly, no direct link between systemic microvasculature and congestion, one of the core characteristics of the syndrome, has yet been investigated. Purpose To provide direct functional and anatomical characterisation of the systemic microvasculature and to explore in vivo parameters of capillary fluid extravasation and lymphatic clearance in HFpEF. Methods In 16 patients with HFpEF and 16 age- and sex-matched healthy controls (72±6 and 68±5 years, respectively) we determined peripheral microvascular filtration coefficient (proportional to vascular permeability and area) and isovolumetric pressure (above which lymphatic drainage cannot compensate for fluid extravasation) by venous occlusion plethysmography and collected a skin biopsy for vascular immunohistochemistry and gene expression analysis (TaqMan). Additionally, we measured brachial flow-mediated dilatation (FMD) and assessed by wire myography the vascular function of resistance arteries isolated from gluteal subcutaneous fat biopsies. Results Skin biopsies in patients with HFpEF showed rarefaction of small blood vessels (82±31 vs 112±21 vessels/mm2; p=0.003) and in ex-vivo analysis (n=6/group) we found defective relaxation of peripheral resistance arteries (p<0.001). Accordingly, post-ischaemic hyperaemic response (fold-change vs baseline, 4.6±1.6 vs 6.7±1.7; p=0.002) and FMD (3.9±2.1 vs 5.6±1.5%; p=0.014) were found to be reduced in patients with HFpEF compared to controls. In the skin of patients with HFpEF we also observed a reduced number (85±27 vs 130±60 vessels/mm2; p=0.012) but larger average diameter of lymphatic vessels (42±19 vs 26±9 μm2; p=0.007) compared to control subjects. These changes were paralleled by reduced expression of LYVE1 (p<0.05) and PROX1 (p<0.001), key determinants of lymphatic differentiation and function. Whilst patients with HFpEF had reduced peripheral capillary fluid extravasation compared to controls (microvascular filtration coefficient, leg 33.1±13.3 vs 48.4±15.2, p<0.01; trend for arm 49.9±20.5 vs 66.3±30.1, p=0.09), they had lower lymphatic clearance (isovolumetric pressure: leg 22±4 vs 16±4 mmHg, p<0.005; arm 25±5 vs 17±4 mmHg, p<0.001). Conclusions We provide direct evidence of systemic dysfunction and rarefaction of small blood vessels in patients with HFpEF. Despite a reduced microvascular filtration coefficient, which is in keeping with microvascular rarefaction, the clearance of extravasated fluid in HFpEF is limited by an anatomically and functionally defective lymphatic system. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation Centre of Research Excellence Award

scholarly journals Quasistatic fluid-fluid displacement in porous media: Invasion-percolation through a wetting transition

2018 ◽  
Vol 3 (10) ◽  
Author(s):  
Bauyrzhan K. Primkulov ◽  
Stephen Talman ◽  
Keivan Khaleghi ◽  
Alireza Rangriz Shokri ◽  
Rick Chalaturnyk ◽  
...  
Keyword(s):  
Porous Media ◽  
Wetting Transition ◽  
Invasion Percolation ◽  
Fluid Displacement

Symmetrization of interface dynamics equations

1992 ◽  
Vol 3 (3) ◽  
pp. 283-297 ◽  
Author(s):  
Leonid K. Antanovskii
Keyword(s):  
Chemical Potential ◽  
General Procedure ◽  
Unsteady Motion ◽  
Free Boundaries ◽  
Piecewise Constant ◽  
Mass Transfer Processes ◽  
Construction Of Self ◽  
Thermodynamic Variables ◽  
Capillary Fluid ◽  
Similar Solutions

The system of conservation laws governing heat and mass transfer processes in a continuous medium is obtained in a symmetric form on the basis of the successive application of fundamental thermodynamic principles. This approach involves reformulating the problem in intensive thermodynamic variables such as the temperature and chemical potential. The equations of capillary fluid mechanics and phase transitions with moving free boundaries are analysed in detail. The unsteady motion of a drop driven by buoyancy forces in an unbounded ambient fluid with dilute surfactants is investigated where the LeChatelier principle is established for an arbitrary surfactant. The general procedure for construction of self-similar solutions for the thermodiffusive Stefan problem with piecewise constant matrices of coefficients is described

Guidelines for Efficient Spot Fluid Displacement in Highly Inclined and Horizontal Wells

2000 ◽  
Author(s):  
A.L. Martins ◽  
U. Sansoni ◽  
J.W. de Camargo ◽  
S.F. de Oliveira
Keyword(s):  
Horizontal Wells ◽  
Fluid Displacement

scholarly journals The anaerobic digestion of sheep manure in self-designed low-cost biogas reactor

2018 ◽  
Vol 12 (2) ◽  
pp. 13-23 ◽  
Author(s):  
Gábor Nagy ◽  
Alexandra Takács ◽  
András Arnold Kállay ◽  
Dóra Mentes
Keyword(s):  
Main Product ◽  
Low Cost ◽  
Base Material ◽  
Solid Material ◽  
Gas Production ◽  
Small Scale ◽  
Fluid Displacement ◽  
Data Collector ◽  
Sheep Manure ◽  
Biogas Reactor

One of the possible utilisation methods for organic wastes is anaerobe decomposition (fermentation). The main product of this process is biogas which is usually used for energy purposes due to its composition (mainly methane and carbon dioxide). The residual solid material after fermentation can be used as soil conditioner. Lab-scale fermentation can be carried out using the “VDI 4630 – Fermentation of organic materials Characterisation of the substrate, sampling, collection of material data, fermentation tests” standard. Based on the conditions described in the standard, a small-scale low-budget reactor system were prepared. The temperature during the holding time was controlled with water bath and the gas production was determined with fluid displacement method. A peristaltic pump was used for the recirculation of the gas to mix the base material. Furthermore, the temperatures of the environment, the water baths and the inside of each reactor was automatically registered on a data collector.

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